It is generally known that material having magnetic properties may be incorporated into a variety of applications. For instance, manufacturers have incorporated magnetic material into educational, instructional and interactive devices for children. Magnets and devices having magnetic properties have a special appeal to children due to the invisible properties of magnetism. There are numerous types of interactive toys, games, appliances and displays in which material having magnetic properties is advantageously used to encourage children to learn and practice basic skills such as reading and arithmetic.
One method of incorporating the invisible properties of magnetism into a product involves adding ferromagnetic material such as iron particles into conventional paints or coatings. The iron particles are blended or mixed into the paint to form magnetic paint. The magnetic paint is then conventionally applied to the surface of a substrate, such as wall board, wood, sheet rock, plywood and the like to make signs and other types of displays having a magnet attracting surface. After the magnetic paint dries, the substrate is then cut into abstract shapes and sizes using conventional tooling.
One of the disadvantages of using the magnetic paint described above is the inability to create detailed images and designs out of the paint. That is, the magnetic paint is generally not adapted to be painted in specific locations or to form very meticulous or complex designs. Rather, the magnetic paint is designed to be applied in large areas simply to create a metallic or magnetic surface. Furthermore, the magnetic surface that is created is generally magnetized over the entire surface, rather than magnetized in specific locations. As a result, many educational and instructional displays used for children that utilize magnetic paint are limited to very basic designs and applications.
U.S. Pat. No. 4,702,700 (Taylor) proposes a book with sheets of magnetic material embedded within the pages, which attract removable magnetic pieces placed onto the surface of the page. Although the sheets do not cover the entire area of the page, they are relatively large, and are not shaped into images or designs. Taylor's magnetic sheets are also sufficiently thick that they will produce a significant bulge in the pages. The bulge is esthetically unattractive, and spoils the invisible effect of the magnetism by making it obvious that there is a concealed artifice within the pages. It is believed that the weight of the magnetic sheets used by Taylor would also be such as to restrict the number and size of the sheets that could practically be included in one book.
U.S. Pat. No. 5,949,050 (Fosbenner et al.) proposes magnetic cards containing, sandwiched within them, a shaped sheet of magnetic material that produces an image by attracting magnetic particles in a liquid imaging cell. The shaped sheets of magnetic material are set into correspondingly shaped cutouts in a filler sheet in the cards. Fosbenner suggests that “a magnetic or magnetizable ink” could be used instead of magnetic sheets, but provides little or no disclosure of how to formulate or apply such a magnetic ink. Because of the use of filler sheets, Fosbenner's cards are thick. The filler sheets also add to the weight. Fosbenner's structure would not be suitable for use as the pages of a book, or as a wall poster or the like.
It is generally known that detailed designs and graphic images may be achieved through the use of a variety of conventional printing processes or techniques. Conventional printing techniques such as silk-screening, lithography, rotogravure, flexography, and the like are used to produce very meticulous designs and images on a substrate. However, most metallic or magnetic paints are not usable with the foregoing printing techniques. As a result, most interactive substrates, particularly those used for educational or instructional products marketed for children, lack any type of detailed designs and graphic images having magnetic properties.